Increased sebum secretion is known to be associated with conditions such as oily hair and scalp and Acne Vulgaris, a chronic disorder of the pilosebaceous units primarily involving the face, chest and back. Sebum is produced by the sebaceous glands which normally are found only in association with hair follicles (therefore the terminology pilosebaceous). The gland continuously forms the complex fatty mixture known as sebum which finds passage up the hair follicle.
Disorders such as acne often result when excess sebum is produced, when the pilosebaceous follicular openings are too small to permit the sebum to pass, or when both conditions are present. In addition, acne lesions generally harbor Propionibacterium acnes on culture. P. acnes appears to be the major source of lipolytic anzymes which hydrolyze the triglycerides of sebum to form irritating free fatty acids.
The primary lesion of acne is the comedo. The open comedo (blackhead) consists of a firm mass of keratin and sebum which blocks and dilates the follicular pore. The upper portion of the blackhead is darkened by slow oxidative changes (not by dirt), the lower portions are white. The closed comedo (whitehead) which is a collection of keratin and sebum with the follicular opening blocked, are potentially the starting point of deep inflammatory lesions.
There have been numerous remedies advanced in the art for the symptomatic treatment of disorders related to increased sebum secretion, such as oily scalp, oily hair and acne, by both topical and internal therapy. Cleansing agents such as abrasives, astringents, shampoos, and special soaps, etc., have been used, however these merely remove surface lipids. These agents make the skin, scalp and hair temporarily appear less oily, but have only a temporary effect on the disorder. Topical drying agents such as sulfur, resorcinol, salicylic acid have been used for the treatment of acne in various lotions and creams. Their efficacy lies only in the capacity for producing erythema (reddening) and desquamation (peeling off), and for causing existing comedones, papules and pustules to peel.
Antibiotics have been among the most effective in the treatment of acne. Long term therapy with antibiotics, however, is not satisfactory for a number of reasons, the most prominent of which is the danger of the development of resistant organisms which would then be immune to treatment with the antibiotic in other therapeutic situations. Antibiotic symptomatic therapy of acne has also been characterized by a new flare-up of symptoms and relapses when the medication was discontinued. There is also the danger of sensitizing reactions to antibiotics which may occur with some patients.
The prior art has also utilized stilbene derivatives (see U.S. Pat. No. 4,326,055 issued Apr. 20, 1982 to Loeliger) and retinoic acids, to treat dermatological disorders. Retinoids act by increasing follicular epithelial production of nonadhering cells, thereby dislodging and sloughing off the comedo contents. Retinoids have also been shown to reduce sebaceous gland size and to inhibit sebum secretion. In many cases, however, these retinoids can cause deleterious side effects such as hypervitaminosis.